Variable-pitch propellers for motor boats and the like, especially for sport craft, are known. Such variable-pitch propellers comprise, as has been described in EP O 231 503, a hub on which a plurality of mounting plates are provided for the respective blades. These mounting plates, for adjustment of the angular positions of the blades about their respective radial axes, are rotated by the blade adjustment mechanism within the hub. The bases of the blades are attached by screws to the respective plates.
This construction allows the blades to be removed from the hub and replaced, for example, by other blades. In many cases this replacement must be effected under water and where bolting of the base of the blade to the plate is necessary, the bolts can be lost, especially when the last bolt is being released, the blade itself may be lost as it is removed or mounted, and, as a general matter, the operation requires considerable dexterity and can be time-consuming. The problem of assembling the blades to the hub, of course, can apply to fixed-pitch propellers as well.